Safety Precaution - Mitsubishi Electric NTXMSM36A142BA Technical & Service Manual

SAFETY PRECAUTION

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1-1. ALWAYS OBSERVE FOR SAFETY
Before obtaining access to terminal, all supply circuit must be disconnected.
Preparation before the repair service
• Prepare the proper tools.
• Prepare the proper protectors.
• Provide adequate ventilation.
• After stopping the operation of the air conditioner, turn
off the power-supply breaker.
• Discharge the condenser before the work involving the
electric parts.
1-2. CAUTIONS RELATED TO NEW REFRIGERANT
Cautions for units utilizing refrigerant R410A
Use new refrigerant pipes.
Avoid using thin pipes.
Make sure that the inside and outside of refrige-
rant piping is clean and it has no contaminants
such as sulfur, oxides, dirt, shaving particles,
etc.,
which are hazard to refrigerant cycle.
In addition, use pipes with specified thickness.
Contamination inside refrigerant piping can cause deterio-
ration of refrigerant oil, etc.
Follow the instructions below to prevent abrasive
components contained in sandpaper and cutting
tools from entering the refrigerant circuit because
those components can cause failures of the
compressor and valves.
• To deburr pipes, use a reamer or other deburring tools,
not sandpaper.
• To cut pipes, use a pipe cutter, not a grinder or other tools
that use abrasive materials.
• When cutting or deburring pipes, do not allow cutting
chips or other foreign matters to enter the pipes.
• If cutting chips or other foreign matters enter pipes, wipe
them off the inside of the pipes.
Store the piping indoors, and keep both ends of
the piping sealed until just before brazing.
(Leave elbow joints, etc. in their packaging.)
If dirt, dust or moisture enters into refrigerant cycle, that
can cause deterioration of refrigerant oil or malfunction of
compressor.
OCHT810A
Precautions during the repair service
• Do not perform the work involving the electric parts with wet
hands.
• Do not pour water into the electric parts.
• Do not touch the refrigerant.
• Do not touch the hot or cold areas in the refrigerating
cycle.
• When the repair or the inspection of the circuit needs
to be done without turning off the power, exercise great
caution not to touch the live parts.
• When opening or closing the valve below freezing
temperatures, refrigerant may spurt out from the gap
between the valve stem and the valve body, resulting in
injuries.
Use a vacuum pump with a reverse flow check
valve.
Vacuum pump oil may flow back into refrigerant cycle and
that can cause deterioration of refrigerant oil, etc.
Use the following tools specifically designed for
use with R410A refrigerant.
The following tools are necessary to use R410A
refrigerant.
Tools for R410A
Gauge manifold
Charge hose
Gas leak detector
Torque wrench
Handle tools with care.
If dirt, dust or moisture enters into refrigerant cycle, that
can cause deterioration of refrigerant oil or malfunction of
compressor.
Do not use a charging cylinder.
If a charging cylinder is used, the composition of refrigera-
nt will change and the efficiency will be lowered.
Ventilate the room if refrigerant leaks during
operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.
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Flare tool
Size adjustment gauge
Vacuum pump adaptor
Electronic refrigerant
charging scale